MOULDING SAND, CASTING SAND, SAND-LESS PIG IRON AND "OPEN SAND" WORK.
The many devices which are employed by furnace-men in controlling the distribution of 20 to 100 tons of molten metal, when tapped, display experience and knowledge which the foundry manager and moulder can often well utilize in founding. Every branch of handling molten metal has its own little '' tricks '' in practice, which have often taken years to perfect, and I propose now to illustrate some of those involved in controlling metal and making " open sand" moulds and casts at a blast furnace, as the information and ideas such study imparts, even though furnaces should abandon casting pigs in sand beds, as referred to oil pages 113 to 116, will prove of value in many ways to general founding.
A moulder, however well experienced, who has never seen a blast furnace, would be very liable to make bad work of things at the start, should he attempt, without any instruction, to direct the making1 and casting off of a floor of pigs. In preparing' a moulding bed for making pigs, the floor is dug1 outnt, and the tap-hole placed at its lowest level, as seen at R. With such an arrangement, when difficulty in tapping and stopping once commences, it often causes the cupola tender much harassing labor, and the founder loss in casting. Any one desiring further information on tapping out and stopping up cupolas is referred to " American Foundry Practice, " page 331.